ST. LOUIS, Missouri (CNN) -- The day after the second presidential debate, an initial poll indicates viewers were split on the performance of President Bush and Sen. John Kerry in Friday night's face-off.

A CNN/USA Today/Gallup poll taken right after the town hall meeting-style debate found respondents giving a slight, statistically insignificant edge to Kerry over Bush: 47 percent of them went for Kerry and 45 percent for Bush. (Full story)

The survey had a margin of error of plus or minus 4 percentage points, meaning the results were too close to indicate a clear winner. It reflected only the immediate impressions of respondents who are registered voters and who watched the debate.

It did suggest that Bush had a significantly better performance than in the first debate, which respondents gave to Kerry by a margin of 53 percent to 37 percent.

At an appearance Saturday in Elyria, Ohio, Kerry claimed victory and joked about Bush's facial expressions.

"The reason he made all those scowling faces is that he saw the latest jobs numbers," Kerry quipped.

On Saturday morning in St. Louis, Bush said "After listening to the litany of complaints and the dour pessimism, I did all I could not to make a bad face."

Bush continued to hammer home the theme that Kerry changes his positions frequently.

Bush said several Kerry statements "don't pass the credibility test," and he asserted that Kerry said with a "straight face" he has only one position on Iraq.

"He must think we've been on another planet," the president said.

Bush also said that Kerry would have to raise taxes to pay for new programs.

"His health care plan alone costs more than $1.2 trillion," Bush said. He said a tax increase on the top income bracket would raise only "$600 billion by our count and $800 billion" by Kerry's.

At his first appearance of the day, Kerry said the president cannot admit his mistakes.

The "most stunning moment of the whole evening" was when Bush was asked to name three mistakes he has made as president, Kerry said.

"The president couldn't even name one mistake" before giving a vague reply about bad appointments, Kerry said.

Kerry reiterated that he thinks the biggest mistakes in the Bush White House have come in Iraq.

"I will succeed in Iraq where this president doesn't know where he is going," Kerry said.

Kerry also is set to stump Saturday in Missouri, a state that could be crucial to the election's outcome, where polls show the candidates are running neck-and-neck. Kerry is expected to visit Florida later Saturday.

Bush also traveled to Iowa and Minnesota for campaign events Saturday.

Testy debate

Friday night, during the town meeting held at Washington University in St. Louis, the president was asked about a report released this week that said Saddam Hussein's regime had no weapons of mass destruction -- a key reason Bush gave for the U.S.-led war in Iraq.

"I wasn't happy when we found out there wasn't weapons," Bush said. "But Saddam Hussein was a unique threat. And the world is better off without him in power. And my opponent's plans lead me to conclude that Saddam Hussein would still be in power, and the world would be more dangerous [if Kerry had been president]."

Kerry fired back, saying the president's policies have left Americans with a huge bill for the war in Iraq.

"If we'd used smart diplomacy, we could have saved $200 billion and an invasion of Iraq, and right now Osama bin Laden might be in jail or dead. That's the war on terror."

After Kerry accused him of going alone into Iraq, Bush interrupted the moderator, ABC's Charles Gibson, to demand that Kerry ask the British or Italian prime ministers if their participation was nonexistent.

Bush repeatedly told Kerry that when it came to his Senate record, "You can run, but you can't hide."

"I don't seen how you can lead this country in a time of war, in a time of uncertainty, if you change your mind because of politics," Bush said.

Kerry used the situation in Iraq to answer a voter's question about him appearing "wishy-washy."

"The president didn't find weapons of mass destruction in Iraq, so he's really turned his campaign into a weapon of mass deception," Kerry said before he sought to explain how his positions on the Patriot Act, education and job creation had not changed.

Bush was much more forceful in his replies than he appeared during the first debate, where his performance was said to have been bumpy and tentative. He began several of his answers by taking a punch at Kerry. (Special Report: The debates)

Jobs were also an issue in the debate. A government report released Friday said that U.S. employers added 96,000 to their payrolls in September, while the unemployment rate stayed unchanged at 5.4 percent.

Bush said the answer was "less regulations if we want jobs here; legal reform if we want jobs here; and we've got to keep taxes low." Kerry answered that he would give tax incentives for companies to stay in the United States using American workers.

Kerry dismissed the president's labeling of him as a tax-and-spend liberal.

"The president is just trying to scare everybody here with throwing labels around. I mean, "compassionate conservative," what does that mean? Cutting 500,000 kids from after-school programs, cutting 365,000 kids from health care, running up the biggest deficits in American history. Mr. President, you're batting 0 for 2," Kerry said.